The work in progress includes: (1) the design, chemical preparation and biological evaluation of synthetic renin inhibitors for the purpose of investigating whether or not a regulatory role for phospholipase A - lysophosphoglyceride exists in the renin-angiotensin system; (2) investigation of the use of these inhibitors for studies on the etiology of chronic hypertension and for possible prognosis of surgery in patients with renal artery disease; (3) investigation of the drug- development potential of phosphatide renin inhibitors and new structurally related derivatives in the medical management of certain types of hypertension in patients; (4) studies on the structure and physicochemical properties of naturally occurring phosphoglyceride and lysophosphoglyceride renin inhibitors with emphasis on the development and improvement of general analytical methods for isolation, separation, and characterization of individual molecular species of these lipids; and (5) evaluation of selected molecular species of naturally occuring and synthetic renin inhibitors developed in this project for their effect on other types of physiological activities such as blood coagulation.